Information processing method and information processing apparatus

Abstract

Markers are laid out to express a predetermined code string by a plurality of continuous markers. The markers which form a marker string include at least two types of markers having different features which can be identified by image processing. Markers detected in the captured image are converted into numerical information, and are collated based on the numerical information and the predetermined code string. Using information associated with the markers, the coordinate information of each collated marker is calculated. The position and orientation of an image capturing device are calculated using the coordinate information. With a simple arrangement, the position and orientation of an image capturing device can be calculated.

1. An information processing method for calculating a position and orientation of an image capturing device which captures an image of a physical space in which a sequence of markers are arranged on a line, comprising:
 detecting a sequence of markers from a captured image; 
 converting the detected sequence of markers into a corresponding sequence of numerical information that indicates positions of the markers; 
 collating a part of a predetermined code string that matches the sequence of numerical information to obtain a collating result; 
 calculating respective coordinate values of the detected sequence of markers in the physical space using the collating result and given information associated with a layout of the sequence of markers; and 
 calculating the position and orientation of the image capturing device using image coordinate values of the detected sequence of markers in the captured image, the coordinate values of the detected sequence of markers in the physical space, and the orientation information of the image capturing device acquired by an arbitrary sensor. 
 
     
     
       2. The method according to  claim 1 , further comprising
 correcting a distortion of an image region which includes the detected sequence of markers, 
 wherein converting the detected sequence of markers includes performing the conversion using an image after the correction is made. 
 
     
     
       3. The method according to  claim 1 , wherein converting the detected sequence of markers includes identifying a type of each of the detected markers. 
     
     
       4. The method according to  claim 3 , wherein converting the detected sequence of markers includes classifying the detected markers into types, and converting each type of marker into different numerical information. 
     
     
       5. The method according to  claim 3 , wherein the identified type includes a size of each of the detected markers. 
     
     
       6. The method according to  claim 1 , wherein the given information associated with the layout of the detected sequence of markers includes at least one of information associated with a layout direction of markers, information associated with an interval between neighboring markers, and coordinates of a reference marker in the sequence of markers. 
     
     
       7. The method according to  claim 1 , wherein the predetermined code string is a code string in which only one autocorrelation function yields “1” within a cycle. 
     
     
       8. The method according to  claim 1 , wherein the sequence of numerical information indicates an order in which the sequence of markers are positioned. 
     
     
       9. A non-transitory computer-readable recording medium containing computer-executable instructions for calculating a position and orientation of an image capturing device which captures an image of a physical space in which a sequence of markers are arranged on a line, the medium comprising:
 computer-executable instructions for detecting the sequence of markers from a captured image; 
 computer-executable instructions for converting the detected sequence of markers into a corresponding sequence of numerical information that indicates positions of the markers; 
 computer-executable instructions for collating a part of a predetermined code string that matches the sequence of numerical information to obtain a collating result; 
 computer-executable instructions for calculating respective coordinate values of the detected sequence of markers in the physical space using the collating result and given information associated with a layout of the sequence of markers; and 
 computer-executable instructions for calculating the position and orientation of the image capturing device using image coordinate values of the detected sequence of markers in the captured image, the coordinate values of the detected sequence of markers in the physical space, and the orientation information of the image capturing device acquired by an arbitrary sensor. 
 
     
     
       10. An information processing apparatus for calculating a position and orientation of an image capturing device which captures an image of a physical space in which a sequence of markers are arranged on a line, comprising:
 a marker detection unit which detects the sequence of markers from the captured image; 
 a conversion unit which converts the detected sequence of markers detected by the marker detection unit into a corresponding sequence of numerical information; 
 a collating unit which collates a part of a predetermined code string that matches the sequence of numerical information to obtain a collating result; 
 a coordinate calculation unit which calculates respective coordinate values of the detected sequence of markers in the physical space using the collating result and given information associated with a layout of sequence of markers; and 
 a position and orientation calculation unit which calculates the position and orientation of the image capturing device using image coordinate values of the detected sequence of markers in the captured image, the coordinate values of the detected sequence of markers in the physical space, and the orientation information of the image capturing device acquired by an arbitrary sensor.